1. Field of the Invention
The present invention relates to a battery pack, and more particularly, to the structure of an air intake of a battery pack mounted in a vehicle.
2. Related Art
A battery pack is mounted on a hybrid electric vehicle, a fuel-cell-powered vehicle, or an electric vehicle for storing electric power to be supplied to a drive motor. A battery pack has a battery stack, and an equipment box into which various pieces of equipment used for controlling the battery stack are to be incorporated.
FIG. 6 shows an external perspective view of a related-art battery pack 100. The battery pack 100 has a battery stack and various types of devices used for controlling the battery stack. The battery stack is incorporated in a first module section 100a, and the various devices are incorporated in a second module section 100b. An air intake 102 is formed in one side surface of the battery pack 100, and the air intake 102 is connected to a duct for cooling air. Cooling air taken in via the air intake 102 flows through the battery stack from bottom to top or from top to bottom to thus cool the battery stack, and is discharged from an air outlet. In order to prevent intrusion of extraneous matter, the air intake 102 is usually provided with a filter, a louver, and the like. FIG. 7 shows a fragmentary enlarged view of the neighborhood of the air intake 102 of the battery pack 100, which is an example where a louver 104 of grid pattern is disposed at the front face of the air intake 102.
Japanese Patent Laid-Open Publication No. Hei 9-45471 describes a configuration which relates to an electromagnetic range and prevents intrusion of extraneous matter and water by interposing, between the air intake and a cooling fan, a shield plate having a drain section in a lower portion thereof.
A louver, or the like, is effective for preventing intrusion of extraneous matter, which consequently occupies an area obstructed by the louver. Accordingly, a loss in the pressure of the cooling air and a decrease in the flow rate of the same arise. Moreover, an area of the louver through which the cooling air flows is susceptible to a reduction in cross section. As a result, the flow rate of the cooling air increases, to thus generate an anomalous sound.